IEEE 802.15.4e is an enhanced MAC layer protocol of 802.15.4 designed for low power and low rate networks. It is suitable for sensor devices with resource constraints; e.g., low power consumption, low computation capabilities, and low memory. Time-Slotted Channel Hopping (TSCH) is a MAC mechanism in IEEE 802.15.4e networks. In TSCH, time is divided into time slots, and every device is time-synchronized to a root node in the network and uses the time slots to communicate/synchronize in the network. The device hops among all channels according to a frequency hopping sequence (FHS) during the time slots. TSCH can achieve higher capacity and provides finer granularity for power savings in IEEE 802.15.4e networks.
Wireless personal area networks (WPANs) are used to convey information over relatively short distances. Unlike wireless local area networks (WLANs), connections effected via WPANs involve little or no infrastructure. This feature allows small, power-efficient, inexpensive solutions to be implemented for a wide range of devices. Two different device types can participate in an IEEE 802.15.4 network: a full-function device (FFD) and a reduced-function device (RFD). An FFD is a device that is capable of serving as a personal area network (PAN) coordinator. An RFD is a device that is not capable of serving as a PAN coordinator. An RFD is intended for applications that are extremely simple, such as a light switch or a passive infrared sensor; it does not have the need to send large amounts of data and only associates with a single FFD at a time. Consequently, the RFD can be implemented using minimal resources and memory capacity.
Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.